[en] Sol-Gel method has been used to deposit pure zinc oxide on glass substrates in two different conditions. The molarity was selected 0.2, 0.3 and 0.4 molar, and the annealing temperature was chosen 450 °C, 500 °C and 550 °C. The structural and morphological properties of the thin films have been investigated using X-ray diffraction and field emission scanning electron microscopy, and some important structural parameters of the optimized sample were determined. By using an electric circuit, their ethanol sensing features have been studied. Several related sensing parameters such as activation energy, optimal operating temperature, dynamic response, sensitivity and response/recovery times of the samples were determined and compared. An uncommon p-type sensing behavior is observed in all samples during the increase in operating temperature (at a temperature of about 370 °C). Considering all the sensing parameters, it seems that the sample Zn₄ (0.4 molar zinc oxide with 450 °C annealing temperature) is optimized as a sensor. (author)